A data communications network generally includes a group of devices, for instance, computers, repeaters, bridges, routers, etc., situated at network nodes and a collection of communication channels for interconnecting the various nodes. Hardware and software associated with the network and particularly the devices permit the devices to exchange data electronically via the communication channels.
The size of networks varies. A local area network (LAN) is a network of devices in close proximity, typically less than one mile, and usually connected by a single cable, for instance, a coaxial cable. A wide area network (WAN) is a network of devices which are separated by longer distances, often connected by, for example, telephone lines or satellite links. In fact, some WANs span the U.S. as well as the world. Furthermore, many of these networks are widely available for use by the public, including commonly universities and commercial industries.
A very popular industry standard protocol for data communication along the networks is the Internet Protocol (IP). This protocol was originally developed by the U.S. government's Department of Defense, and has been dedicated for public use by the U.S. government. In time, the Transmission Control Protocol (TCP) and the Unreliable Datagram Protocol (UDP) were developed for use with the IP. The former protocol (TCP/IP) is a protocol which guarantees transfer of data without errors, as it implements certain check functionality, and the latter protocol (UDP/IP) is a protocol which does not guarantee transfer of data, but requires much less overhead than the TCP/IP platform. Furthermore, in order to keep track of and manage the various devices situated on a network, the Simple Network Management Protocol (SNMP) was eventually developed for use with a UDP/IP platform. The use of the foregoing protocols has become extensive in the industry, and numerous vendors now manufacture many types of network devices which can employ these protocols.
Many management software packages ("management platforms") are presently available for implementing "management stations" on a network, and particularly, in connection with the SNMP. Examples of commercially available SNMP management software packages include OpenView from the Hewlett-Packard Company (the assignee herein), NetView/6000 from IBM Corp., Spectrum from Cabletron Systems, Inc., NetLabs/Manager from NetLabs, Inc., and SunNet Manager from SunConnect, Inc. The nodes on a network and their interconnections, oftentimes referred to as the network "topology," are best displayed in a graphical format, and most, if not all, of the available management software packages provide for this feature. Typically, with these packages, a network can be viewed from different vantage points, depending on the scope of the view desired. For example, one view of the network could be a very wide encompassing view of all nodes on the entire network. A second view could be a view of those portions of a network within a local range, for example, within a particular site or building. A third view of a network, often called a segment, could be a view of the nodes attached to a particular LAN cable.
Hewlett-Packard's very successful OpenView has been the subject of several patents, including for instance, U.S. Pat. No. 5,185,860 issued to J. C. Wu on Feb. 9, 1993, and U.S. Pat. No. 5,276,789 issued to Besaw et al. on Jan. 4, 1994, the disclosures of which are incorporated herein by reference. U.S. Pat. No. 5,185,860 describes an automatic discovery system for a management station for determining the network devices and interconnections of a network, or the topology. U.S. Pat. No. 5,276,789 describes a graphic display system for a management station for graphically displaying the topology of a network and provides for various views (including, internet, segment, and node views) that can be requested by a user.
Although the presently available SNMP management stations are meritorious to an extent, the art of SNMP management stations is still in a state of infancy, and the performance of these management stations can still be enhanced and optimized. A specific area where optimization is envisioned involves the integrating applications which are associated with the management stations and which can provide additional information about network devices, for example, routers. The additional information could include, for example, device configuration information, device status, performance parameters, additional topology information, etc. However, in prior art management stations, this additional information is oftentimes not made available to the user. One reason that this additional information is not made available is that these systems suffer from an inadequate interface between the integrating applications and the display map generator within these systems.
More specifically, many management stations have on-demand submap capabilities. One such example is Hewlett-Packard's OpenView. In on-demand submap systems, a submap corresponds with each view of the network to be displayed. The system map is the collection of all submaps. In these on-demand submap systems, and particularly, the OpenView system, the user specifies which submaps the user wishes to have available, and hence, specifies the submaps which are resident within the map. Moreover, the user can also open, or "explode," a submap during operation, even though it is not specified as resident in the map. In this case, the submap is generated immediately from topology data when the user prompts the management station to open the submap, hence the name on-demand. However, the foregoing design is problematic. First, if a submap is not resident in the map, and the user opens the submap, then an integrating application cannot adequately determine what additional information to provide to the management station, due to time constraints in opening the desired submap, and the user is therefore not advised of this additional information. In other words, the integrating applications need time to analyze the topology data and time to generate the additional information for display to the user.
Another problem with current designs is that for nonresident submaps, integrating applications are unable to alert the user of critical information until the user explodes the submap. It is desirable to alert the user as soon as an anomaly is detected.
Furthermore, in prior art management stations, once a submap has been created, it remains in the system's map from then on, even if the integrating applications no longer need the submap. This predicament undesirably uses valuable memory space. This situation also needlessly expends processor time, as some events, or changes in network topology, will unnecessarily be processed for updating some of the unnecessary resident submaps. Thus, a need exists in the industry for a system and method for better interfacing integrating applications to an on-demand submap system, for minimizing memory requirements thereof, and for optimizing performance (including speed) thereof.